The present invention relates generally to a hose clamp, and particularly to a hose clamp of the xe2x80x9cTxe2x80x9d-bolt variety.
Hose clamps are conventionally employed to seal the connection between a hose or tubing and a cylindrical fitting or nipple. The clamps encircle at least a portion of the outer circumference of a hose disposed about a fitting, and are caused to constrict, i.e., to impart a radially inward directed compressive force to seal the hose to the fitting. Hose clamps of the xe2x80x9cTxe2x80x9d-bolt variety are also known, and examples thereof are described for instance in U.S. Pat. Nos. 2,852,832 and 5,329,673. The utilization of T-bolt clamps presents many advantages over other types of hose clamp, including that of being generally adjustable over a range of hose diameters and of accommodating relatively higher loads than other clamp types, such as those employing worm-type or screw connections, or deformable ear type constricting members.
T-bolt clamps conventionally comprise an outer generally resilient thin band portion for encircling a greater portion of the outer circumference of a hose and having opposing ends bent radially outward and upon themselves to form opposing looped band ends, and a T-bolt extending between the opposed looped band ends through apertures therein, tightening of which forces the looped ends to draw toward one another thus reducing the band""s circumference to constrict the band about the outer circumference of the hose. The incorporation of a bridge member in T-bolt clamp constructions, comprising generally resilient thin shorter length strip for extending along the outer circumference of the hose between the outer band""s opposed band ends and radially inward of the T-bolt, is known. These bridge members have been employed in T-bolt clamp configurations for preventing or reducing the incidence of the formation of a bulge, or a portion of the hose wall from moving radially away from the underlying fitting in the region between the band""s looped ends as a consequence of the looped ends being drawn together during the clamp tightening process.
A step or ridge is generally formed along the inner circumference of T-bolt clamps incorporating a bridge member between the inner surface of the outer band and the inner surface of the bridge member at either end of the bridge, resulting in an interruption in the sealing pressure that the clamp imparts on the hose. In many instances this interruption does not pose a significant problem since a relatively lower modulus hose material can generally fill the gap formed by this step with tightening of the clamp. This is generally also the case where relatively thicker walled hose, of e.g., 0.25 inches in thickness or more is employed.
This step or ridge can be problematic however in applications involving relatively higher modulus hose materials, e.g., textile-reinforced hose, and/or relatively thin-walled hose, wherein the hose""s ability to fill the gap formed by the step is restricted. In such cases, this interruption in sealing pressure can lead to increased risk of leakage or hose damage. For example, where in the instance of a conventionally dimensioned T-bolt clamp the step between the inner surface of the band and the inner surface of the bridge is approximately 0.025 inches, but the relevant hose wall thickness is only 0.090 inches, a sufficient amount of hose material to fill the gap formed by the step with tightening of the clamp is not generally available.
Prior attempts at providing a T-bolt clamp capable of maintaining uniform radial compressive force around a hose circumference have involved the utilization of a flexible inner liner for circumscribing the hose in a position beneath the clamp""s outer band, and having a tongue portion at either end thereof for mating engagement with the tongue at the liner""s opposite end, such as described for example in aforementioned U.S. Pat. No. 2,852,832. The utilization of an inner liner has certain disadvantages compared to the utilization of a bridge, including the added material costs and labor steps required with inner liners that must extend around the entire circumference of the hose. In addition, the increased length of the inner liner compared to the relatively short bridge member involves greater complexity in terms of assembly and maintenance to ensure proper alignment of the liner beneath the outer band.
The present invention provides a T-bolt hose clamp comprising a band member for encircling a portion of the outer circumference of an underlying hose, and comprising a radially outward facing surface and a radially inward facing surface, a length extending from a first band end to an opposing second band end, each end having a portion turned outward to form an opposing loop member, and a width extending from a first lateral band edge and an opposite second lateral band edge; a bolt member for extending between the loop members, and comprising a transverse portion and a shank portion; and a bridge member for extending from the band""s first end to its second end in a position radially inward of said bolt member, and comprising a radially inward facing surface and a radially outward facing surface, a first bridge end and an opposite second bridge end, wherein a portion of the bridge""s radially outward facing surface is in opposing relation to at least a portion of the inward facing surface of said band member; and wherein the band member possesses at least one radially inward projecting rib extending longitudinally along at least a portion of the band from the point at which the inner surface of the band meets each bridge end, and being formed such that in the clamp""s engaged position about the hose, at least a radially innermost portion of the rib is in substantially the same cross-sectional plane as the inner surface of the bridge.
In a further embodiment, the bridge of the clamp is provided with at least one aperture extending inward from at least one bridge end, which aperture is formed and arranged to slidingly receive the rib of the band as the clamp is tightened in place such that at least a portion of the rib extends within at least a portion of the aperture.
In yet another embodiment, the band is provided with two such longitudinally extending ribs, each such rib being located at an opposing band lateral edge, and the bridge is provided with two complementary apertures for slidingly receiving the ribs. In a further embodiment, the bridge is provided with a reduced width portion at least one bridge end, the lateral periphery of which defines in each case a boundary of one of two apertures so formed in the bridge member.